Image.new behaviour differs from Playdate's

[AntonPetrov83]

Playdate implementation of image.new()

1. Allows image paths to have extension specified like in the "2020" standard example:

	local bgImg = gfx.image.new('images/background.png')

2. Returns nil if image file not found. Mentioned above standard example "2020" tries to load non-existent images and fails quitely:

local explosionImages = {}
for i = 1, 8 do
	explosionImages[i] = gfx.image.new('images/x/'..i)
end